|Publication number||US5179710 A|
|Application number||US 07/851,247|
|Publication date||Jan 12, 1993|
|Filing date||Mar 13, 1992|
|Priority date||Nov 30, 1988|
|Publication number||07851247, 851247, US 5179710 A, US 5179710A, US-A-5179710, US5179710 A, US5179710A|
|Original Assignee||Laboratoire Europeen De Recherches Electroniques Avancees|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (9), Non-Patent Citations (4), Referenced by (28), Classifications (5), Legal Events (6)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application is a continuation of application Ser. No. 07/441,656, filed on Nov. 27, 1989, now abandoned.
1. Field of the Invention
The invention pertains to an interface with an electrical supply.
2. Description of the Prior Art
The space occupied by electronic instruments can be reduced by taking advantage of the miniaturization of modern components. However, certain instruments such as, for example, computers have to be capable of communicating with the exterior by means of appropriate interfaces and connectors. Thus, the reduction of the number of pins of the connectors enables the space that it occupies to be reduced, but limits its possibilities. For example, in serial links between computers, there has been a change from a connector with 25 pins to a connector with 9 pins called SUB D9M. This connector has a smaller space factor but all its pins are used. Thus it is not possible to add on, for example, a supply for an external peripheral. Thus, in prior art computers, it is not possible to use the serial link to connect an external peripheral that has to be supplied with current, for example a peripheral such as a MIDI interface designed for the driving of musical instruments. Now, it turns out that certain signals emitted by the serial link may, provided that they are amplified, act as external electrical supplies inasmuch as their voltage remains constant for the stage during which the external peripheral needs to be supplied. For example, the signal called DTR or DTR (Data Terminal Ready) is amplified to supply an external MIDI interface. The MIDI interface draws 5 volts from a voltage approximately equal to 12 volts given by the interface according to the present invention.
A main object of the invention is an interface comprising means to amplify one of the signals so that it is possible to provide an electrical supply to an external device.
Another object of the invention is an interface wherein an amplification means includes a transistor.
Another object of the invention is an interface wherein the transistor is of the NPN type.
Another object of the invention is an interface which is an RS 232 type serial interface.
Another object of the invention is an interface wherein the DTR (Data Terminal Ready) signal of the RS 232 serial interface is used.
Another object of the invention is an interface comprising a resistor parallel mounted with the transistor.
Another object of the invention is an interface comprising a nine-pin connector of the SUB D9M type.
Another object of the invention is a computer including an interface.
Another object of the invention is a computer capable of working under the MS-DOS operating system.
Another object of the invention is a device including a MIDI interface and a computer wherein the MIDI interface is connected to the computer by means of the interface.
The invention will be better understood from the following description and from the appended figures, given as non-restrictive examples, wherein:
FIG. 1 is a diagram of a device according to the present invention;
FIG. 2 is a diagram of a particular exemplary embodiment of the device according to the present invention;
FIG. 3 is a diagram of a device according to the present invention.
FIG. 1 shows a digital instrument 22, for example a computer having a connector 10. The connector 10 is connected to an interface 21. The connections may be for the communication of data, for example digital data, between the computer and the exterior. On at least one of the contacts of the connector, there is an electrical supply obtained from the signal given by the interface 21. The electrical supply is obtained by amplification by amplifiers 30 of the signals given by the interface 21. The amplifiers 30 have to be capable of giving at least the current asked for by the external peripheral. However, it is possible to restrict the maximum current, for example to comply with standards.
It is clear that the invention is not restricted to computers, and that other devices having digital outputs such as, for example, digital synthesizers, digital optical disk readers and household appliances comprising the control interfaces do not go beyond the scope of the present invention.
FIG. 2 shows a particularly advantageous example of the device according to the present invention, concerning a serial interface and a male connector 10 of the SUB D9M type. The serial interface includes, for example, an integrated circuit 11 marketed by the firm NATIONAL SEMICONDUCTOR under reference 8250, an output buffer 13, marketed by the firm MOTOROLA under reference 1488 and two input buffers 12 marketed by the firm MOTOROLA under reference 1489.
In the example shown in FIG. 2:
the terminal 1 is connected through a circuit 12 to the RLSD signal of the circuit 11;
the terminal 2 is connected through the circuit 12 to the SIN signal of the circuit 11;
the terminal 3 is connected through the circuit 13 to the SOUT signal of the circuit 11;
the terminal 4 is connected through the circuit 13 to the DTR signal of the circuit 11;
the terminal 5 is connected to the ground;
the terminal 7 is connected through the circuit 12 to the DSR signal of the circuit 11;
the terminal 7 is connected through the circuit 13 to the RTS signal of the circuit 11.
the terminal 8 is connected through the circuit 12 to the CTS signal of the circuit 11;
the terminal 9 is connected through the circuit 12 to the RI signal of the circuit 11.
In the device according to the present invention, it is imperative to determine a signal which, firstly, is liable to give the desired supply voltage and, secondly, is not disturbed by the presence of the amplification device. In the example illustrated in FIG. 2, the DTR signal is used. In the RS 232 serial interfaces, the DTR signal is equal to more than 12 volts to indicate a logic level "1" and is equal to less than 12 volts to indicate a logic level "0".
In the exemplary embodiment shown in FIG. 2, the output of the circuit 13 is connected firstly to the base of an NPN transistor 14 and, secondly, to the resistor 15. The resistor 15 is, for example, equal to 1000 ohms. The emitter of the transistor is connected to the terminal 4 of the connector 10. The collector of the transistor is connected to a+12 volts supply. During normal operation, when the MIDI interface is connected to the connector 10, the DTR signal is positive, the transistor 14 conducts the current and thus enables the supplying of the MIDI interface. In normal use of the RS 232 serial interface, when the voltage of the DTR signal is equal to +12 volts, this signal gets propagated to the terminal 4 without being modified by the transistor 14 of the resistor 15. On the other hand, when the DTR signal is equal to -12 volts, the transistor 14 is off and the signal passes by means of the resistor 15.
It is thus seen that the serial interface behaves exactly as usual but that, if it is necessary, it further enables the provision of an electrical supply. It is, of course, possible to restrict the maximum current liable to be put through by the serial interface for safety reasons or to comply with standards. For example, it is possible to take a transistor that cannot put through a current of more than 20 mA or to serially connect a resistor limiting the current.
If it is sought to give a negative current, advantageously a PNP transistor will be used, with a -12 volts signal.
FIG. 3 shows a computer 22 according to the present invention, connected by means of a MIDI interface 32 to a synthesizer 21 for example. The MIDI interface 32 is connected by means of the connector 10 of the RS 232 interface 21 to the computer 22. Should the MIDI interface 32 require a supply voltage of 5 volts, it comprises, for example, a 5-volt Zener diode placed between the outputs 5 and the outputs 4 of the connector 10. In the device according to the invention, it is possible to connect a computer 22 through a serial interface 21 and a 9-pin connector of the SUB D9M type to a MIDI interface 32. Thus, firstly there is a saving of a connector dedicated to the MIDI interface and, secondly, it is possible to reduce the size of the connector 10.
The invention can be applied to the making of interfaces capable of giving an electrical supply to an external device, as well as to computers having such interfaces.
The invention can be applied chiefly to the making of computers capable of working under the MS-DOS operating system and capable of giving a supply voltage to the MIDI interface by means of an RS 232 serial interface and a SUB D9M connector.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4144565 *||Jan 6, 1977||Mar 13, 1979||International Business Machines Corporation||Input/output interface connector circuit for repowering and isolation|
|US4578533 *||Feb 17, 1984||Mar 25, 1986||Universal Data Systems, Inc.||Switchable line powered modem|
|US4592069 *||Feb 8, 1984||May 27, 1986||Redding Robert James||Line powered modem|
|US4631698 *||Jul 29, 1983||Dec 23, 1986||Iq Technologies, Inc.||Interface apparatus|
|US4794525 *||Feb 4, 1987||Dec 27, 1988||Motorola, Inc.||External interface control circuitry for microcomputer systems|
|US4851715 *||Dec 20, 1988||Jul 25, 1989||Texas Instruments Incorporated||Schottky-clamped transistor logic buffer circuit|
|US4866602 *||Nov 9, 1987||Sep 12, 1989||Microsoft Corporation||Power supply for a computer peripheral device which positions a cursor on a computer display|
|US4884287 *||Apr 1, 1988||Nov 28, 1989||Ncr Corporation||Converter device for interconnecting systems having different communication standards|
|GB2154834A *||Title not available|
|1||David J. Comer, "Modern Electronic Circuit Design" 1968 Addison-Wesley Publishing Company pp. 187-190.|
|2||*||David J. Comer, Modern Electronic Circuit Design 1968 Addison Wesley Publishing Company pp. 187 190.|
|3||Electronic Design, vol. 31, No. 13, Jun. 23, 1983, pp. 166 & 168, Waseca, Minn., Denville, N.J. USA, W. Freeman, "Remote Display Draws Power from RS-232 Line".|
|4||*||Electronic Design, vol. 31, No. 13, Jun. 23, 1983, pp. 166 & 168, Waseca, Minn., Denville, N.J. USA, W. Freeman, Remote Display Draws Power from RS 232 Line .|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US5301334 *||Oct 16, 1991||Apr 5, 1994||Kabushiki Kaisha Toshiba||Function expansion unit capable of supplying power to computer|
|US5408669 *||Jul 5, 1994||Apr 18, 1995||Dell Usa, L.P.||Computer system for sensing a cable-connected peripheral and for supplying power thereto|
|US5430883 *||Jan 5, 1994||Jul 4, 1995||Kabushiki Kaisha Toshiba||Function expansion unit capable of supplying power to computer|
|US5438678 *||Mar 23, 1993||Aug 1, 1995||Smith; Peter L.||Self-powered computer accessory device for power extraction from attached data signals and method of operating thereof|
|US5515373 *||Jan 11, 1994||May 7, 1996||Apple Computer, Inc.||Telecommunications interface for unified handling of varied analog-derived and digital data streams|
|US5550985 *||May 2, 1994||Aug 27, 1996||Hewlett-Packard Company||Special purpose computer for demonstrating peripheral devices such as printers in which power is withdrawn from the port connection of the peripheral device|
|US5555421 *||Nov 23, 1993||Sep 10, 1996||Kistler Instrument Company||Bidirectional interface for interconnecting two devices and the interface having first optical isolator and second optical isolator being powered by first and second device ports|
|US5619659 *||Jun 30, 1995||Apr 8, 1997||Elonex Ip Holdings Ltd.||System for extending ISA bus without using dedicated device driver software by using E2 P2 interface which provides multiplexed bus signal through standard parallel port connector|
|US5630170 *||May 19, 1995||May 13, 1997||Kabushiki Kaisha Sega Enterprises||System and method for determining peripheral's communication mode over row of pins disposed in a socket connector|
|US5649213 *||Apr 22, 1996||Jul 15, 1997||Sun Microsystems, Inc.||Method and apparatus for reducing power consumption in a computer system|
|US5659800 *||Oct 6, 1993||Aug 19, 1997||International Technologies & Systems Corporation (Its)||System for directly sending undecoded raw signals from reader device via external slave interface to personal computer through communication port without first decoding the signals|
|US5664204 *||Apr 30, 1996||Sep 2, 1997||Lichen Wang||Apparatus and method for supplying power and wake-up signal using host port's signal lines of opposite polarities|
|US5721937 *||Mar 3, 1997||Feb 24, 1998||Sun Microsystems, Inc.||Method and apparatus for reducing power consumption in a computer system by placing the CPU in a low power mode|
|US5884086 *||Apr 15, 1997||Mar 16, 1999||International Business Machines Corporation||System and method for voltage switching to supply various voltages and power levels to a peripheral device|
|US6134669 *||Mar 27, 1998||Oct 17, 2000||Trans World Marketing Corp.||Printer powered printer driver|
|US6446868||Nov 23, 1998||Sep 10, 2002||Informatics, Inc.||Scanning system for decoding two-dimensional barcode symbologies with a one-dimensional general purpose scanner|
|US8155012||Sep 26, 2008||Apr 10, 2012||Chrimar Systems, Inc.||System and method for adapting a piece of terminal equipment|
|US8902760||Sep 14, 2012||Dec 2, 2014||Chrimar Systems, Inc.||Network system and optional tethers|
|US8942107||Feb 10, 2012||Jan 27, 2015||Chrimar Systems, Inc.||Piece of ethernet terminal equipment|
|US9019838||Sep 14, 2012||Apr 28, 2015||Chrimar Systems, Inc.||Central piece of network equipment|
|US9049019||Sep 14, 2012||Jun 2, 2015||Chrimar Systems, Inc.||Network equipment and optional tether|
|US20040062203 *||Sep 23, 2003||Apr 1, 2004||Austermann John F.||System for communicating with electronic equipment|
|US20090022057 *||Sep 26, 2008||Jan 22, 2009||Austermann John F Iii||System and method for communicating with objects on a network|
|EP1087282A2 *||Jun 24, 2000||Mar 28, 2001||elero GmbH||Interface|
|EP1087282A3 *||Jun 24, 2000||May 23, 2001||elero GmbH||Interface|
|WO1995019087A2 *||Jan 11, 1995||Jul 13, 1995||Apple Computer, Inc.||Telecommunications interface for unified handling of varied analog-derived and digital data streams|
|WO1995019087A3 *||Jan 11, 1995||Aug 31, 1995||Apple Computer||Telecommunications interface for unified handling of varied analog-derived and digital data streams|
|WO1998010344A1 *||Sep 4, 1997||Mar 12, 1998||Penware Systems, Inc.||Powering signature pad from lap-top computer|
|U.S. Classification||713/300, 703/25|
|Sep 29, 1992||AS||Assignment|
Owner name: LABORATOIRE EUROPEEN DE RECHERCHES ELECTRONIQUES A
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:COSCHIERI, JEAN-CLAUDE;REEL/FRAME:006276/0762
Effective date: 19891211
|Jul 8, 1996||FPAY||Fee payment|
Year of fee payment: 4
|Jul 5, 2000||FPAY||Fee payment|
Year of fee payment: 8
|Jul 28, 2004||REMI||Maintenance fee reminder mailed|
|Jan 12, 2005||LAPS||Lapse for failure to pay maintenance fees|
|Mar 8, 2005||FP||Expired due to failure to pay maintenance fee|
Effective date: 20050112